The imagery on this page is the basis for a paper entitled Structural Extremes in a Cretaceous Dinosaur, by P.C. Sereno, J.A. Wilson, L.A. Witmer, J.A. Whitlock, A. Maga, O. Ide, and T.B. Rowe (PLoS ONE 2(11):e1230). The abstract is as follows:

Fossils of the Early Cretaceous dinosaur, Nigersaurus taqueti, document for the first time the cranial anatomy of a rebbachisaurid sauropod. Its extreme adaptations for herbivory at ground-level challenge current hypotheses regarding feeding function and feeding strategy among diplodocoids, the larger clade of sauropods that includes Nigersaurus. We used high resolution computed tomography, stereolithography, and standard molding and casting techniques to reassemble the extremely fragile skull. Computed tomography also allowed us to render the first endocast for a sauropod preserving portions of the olfactory bulbs, cerebrum and inner ear, the latter permitting us to establish habitual head posture. To elucidate evidence of tooth wear and tooth replacement rate, we used photographic-casting techniques and crown thin sections, respectively. To reconstruct its 9-meter postcranial skeleton, we combined and size-adjusted multiple partial skeletons. Finally, we used maximum parsimony algorithms on character data to obtain the best estimate of phylogenetic relationships among diplodocoid sauropods. Nigersaurus taqueti shows extreme adaptations for a dinosaurian herbivore including a skull of extremely light construction, tooth batteries located at the distal end of the jaws, tooth replacement as fast as one per month, an expanded muzzle that faces directly toward the ground, and hollow presacral vertebral centra with more air sac space than bone by volume. A cranial endocast provides the first reasonably complete view of a sauropod brain including its small olfactory bulbs and cerebrum. Skeletal and dental evidence suggests that Nigersaurus was a ground-level herbivore that gathered and sliced relatively soft vegetation, the culmination of a low-browsing feeding strategy first established among diplodocoids during the Jurassic.

About the Species

This specimen, the third cervical vertebra, was collected from the Aptian-Albian horizons of the Tegama Group, Gadoufaoua region, Niger. It was made available for scanning by Dr. Paul Sereno of the University of Chicago. Funding for scanning and image processing was provided by Dr. Sereno. Additional funding for image processing was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Timothy Rowe of the Department of Geological Sciences, The University of Texas at Austin.

About this Specimen

The specimen was scanned by Matthew Colbert on 2 February 2005 along the horizontal axis for a total of 590 slices. Each 1024x1024 pixel slice is 0.25 mm thick, with an interslice spacing of 0.21 mm (resulting in a slice overlap of 0.04 mm) and a field of reconstruction of 290 mm.

Erickson, G.M. 1996. Incremental lines of von Ebner in dinosaurs and the assessment of tooth replacement rates using growth line counts. Proceedings of the National Academy of Sciences USA 93:14623-14627.

Fiorillo, A.R. 1998. Dental microwear patterns from the sauropod dinosaurs Camarasaurus and Diplodocus: evidence for resource partitioning in the Late Jurassic of North America. Historical Biology 13:1-16.